Thorgan Hazard will join his older brother Eden at Stamford Bridge next season after Chelsea confirmed his transfer from Ligue 2 side Lens.
The 19-year-old had only played 11 times for the Ligue 2 club but the Blues clearly see potential in midfielder Hazard, who could be immediately loaned to another club.
His brother signed for Chelsea from Ligue 1 club Lille in June for £32 million.
Thorgan Hazard in action